Christopher Watts is escorted into the courtroom before his bond hearing at the Weld County Courthouse on Thursday, Aug. 16, 2018, in Greeley, Colo.

RJ Sangosti, The Denver Post

Colorado Bureau of Investigation Director John Camper talks to media on Aug. 16, 2018 in Frederick. Frederick police have arrested Shanann's husband Christopher Watts on suspicion of murdering the three.

RJ Sangosti, The Denver Post

Members of the community gather for a candlelight vigil to honor Shanann, Bella and Celeste Watts outside the family's home on Aug. 17, 2018, in Frederick.

RJ Sangosti, The Denver Post

Aubriella Luna, 8, joined others from her community for a candlelight vigil to honor Shanann, Bella and Celeste Watts outside the family's home Aug. 17, 2018, in Frederick.

RJ Sangosti, The Denver Post

Colleen Hendrickson and her grandson Ezra Reed, 3, who lives down the street, place flowers at a makeshift memorial to Shanann, Bella and Celeste Watts, who have been missing since Monday, outside the family home on Aug. 16, 2018 in Frederick. Frederick police have arrested Shanann's husband Christopher Watts on suspicion of murdering the three.

RJ Sangosti, The Denver Post

Residents stand in front of a makeshift memorial for Shanann, Bella and Celeste Watts outside the family's home on Aug. 17, 2018 in Frederick. Frederick police have arrested Shanann's husband Christopher Watts on suspicion of killing the three.

RJ Sangosti, The Denver Post

Nancy Lee takes a moment after placing flowers at a makeshift memorial for Shanann, Bella and Celeste Watts, outside the family's home on Aug. 17, 2018 in Frederick. Frederick police have arrested Shanann's husband, Christopher Watts, on suspicion of killing the three.

GREELEY — The Frederick man charged with murder Monday in the deaths of his pregnant wife and two preschool-aged daughters told police he caught his wife strangling one of their children, leading him to then strangle her in “a rage.”

Christopher Watts told a Frederick Police Department detective that he saw his wife, Shanann, strangling their youngest daughter, 3-year-old Celeste, on a baby monitor. Their oldest daughter, 4-year-old Bella, already was “sprawled out on her bed and blue,” according to an arrest-warrant affidavit released by the courts Monday. The affidavit offered new details about the investigation of Christopher Watts, 33, and the deaths of his 34-year-old wife and two daughters.

“Chris said he went into a rage and ultimately strangled Shanann to death,” the affidavit said.

The affidavit was unsealed by a judge Monday afternoon after Weld County District Attorney Michael Rourke filed charges against Watts, including five counts of first-degree murder, one count of unlawful termination of pregnancy in the first degree and three counts of tampering with a deceased human body.

Watts will appear in Weld County District Court at 10 a.m. Tuesday for an advisement hearing.

Lewis Geyer, Longmont Times-Call

Frank Rzucek cries after speaking at a news conference at which Weld County District Attorney Michael Rourke announced the charges against Christopher Watts. Rzucek is the father of Shanann Watts. To the left of Frank is Shanann’s brother and Frank’s son, Frankie.

On Monday, Shanann Watts’ family made their first public statement since her and the girls’ deaths when her father, Frank Rzucek, addressed the media at a news conference at the Weld County Courthouse. Reading from a folded piece of paper and with his voice shaking, he thanked the Frederick police for their investigation and locating his family’s burial sites. He also thanked the public for their outpouring of support.

“Keep the prayers coming for our family,” Rzucek said.

The tragic deaths have shaken Watts’ friends and family as well as strangers who have been horrified of accusations of a man killing his pregnant wife and two young daughters. On Friday night, more than 150 people attended a candlelight vigil outside the Watts family home, where a growing memorial of stuffed animals, flowers and candles rests. National media attended Monday’s news conference at which Rourke announced the charges.

Before Watts confessed to police, he told them his wife and children were missing. Shanann had returned home around 1:48 a.m. Tuesday from a work trip in Arizona, and Watts said he asked her for a separation around 4 a.m. He was having an affair with co-worker, the affidavit said.

“Chris stated it was a civil conversation and they were not arguing but emotional,” the affidavit said.

He also told the detective that they both cried. Shanann Watts wanted to go to a friend’s house the next day, the affidavit said.

Shanann Watts was reported missing on Wednesday after failing to answer messages from a friend and missing a doctor’s appointment. Watts was 15 weeks pregnant with a son, who would have been named Neko. The pregnancy had been difficult, the affidavit said.

The friend who reported her missing also called Watts and asked him to come home to check on his family. Police arrived at their Frederick house before Watts, the affidavit said. An officer who went into the house with Watts’ permission found Shanann’s purse, cell phone and medication inside.

The next day, after the mother and children had not come home, police issued a public notification that they were missing. The Colorado Bureau of Investigation and the FBI joined the search.

Lewis Geyer, Longmont Times-Call

Weld County District Attorney Michael Rourke speaks during a news conference announcing the charges against Christopher Watts in the death of his pregnant wife and daughter.

As the search intensified, Watts gave interviews to Denver TV stations in which he pleaded for his wife and children to come home.

Two days into the investigation, Watts told a detective “he would tell the truth after speaking with his dad,” the affidavit said. Watts’ father already was at the police station.

“After being allowed to speak with his father, Chris stated (that) after he told Shanann he wanted a separation, he walked downstairs for a moment and then returned to his bedroom to speak to Shanann again,” the affidavit said.

That’s when Watts told police he saw his wife strangling Celeste on the baby monitor, which was on a nightstand by their bed.

Rourke was tight-lipped during the Monday news conference, citing the ongoing investigation. It is too early to say whether he’ll consider the death penalty in this case, to which he has assigned three prosecutors, Rourke said.

He explained the charge of unlawful termination of a pregnancy, which is a relatively new crime in Colorado. The state does not have a law that allows district attorneys to charge someone with murder over the death of a fetus. In 2015, Dynel Lane, who cut an unborn child out of Longmont woman Michelle Wilkins’ womb, was convicted of unlawful termination of a pregnancy, along with attempted first-degree murder and four counts of assault.

On Friday, the Weld County Coroner’s Office confirmed the three bodies found at the oil tanks, which are owned by Anadarko Petroleum Company, belonged to Shanann, Bella and Celeste. However, a cause of death has not yet been determined.

Police discovered a bed sheet in the field near the tank battery that matched the pattern of other linens found in a kitchen trash can at the Watts home earlier that day, according to the affidavit.

Watts had worked for Anadarko until Wednesday, when he was fired.

Warning: The following video may contain content that disturbs viewers.

Noelle Phillips, a Nashville native and a Western Kentucky University journalism school grad, covers law enforcement and public safety for The Denver Post. She has spent more than 20 years in the newspaper world. During that time, she's covered everything from rural towns in the Southeast to combat in the Middle East. The Denver Post is her fifth newspaper and her first in the West.

Elizabeth Hernandez is a Denver Post reporter covering breaking news and a little bit of everything else, too. A former education reporter at both The Post and Boulder Daily Camera, Elizabeth is passionate about using her platform to tell the stories of underrepresented Coloradans in an accurate, compassionate, engaging manner. She started at The Denver Post as an intern in 2014 and just kept coming to work until they hired her.

Kirk Mitchell is a general assignment reporter at The Denver Post who focuses on criminal justice stories. He began working at the newspaper in 1998, after writing for newspapers in Mesa, Ariz., and Twin Falls, Idaho, and The Associated Press in Salt Lake City. Mitchell first started writing the Cold Case blog in Fall 2007, in part because Colorado has more than 1,400 unsolved homicides.

Denver Sheriff Patrick Firman's resignation this week culminated years of mistrust from deputies and community activists, who said that was the price of filling the position with a man who was never the right person for the job.